Objective To investigate the effects of Fuzheng Sanjie Formula on immune function and microRNA-335-5p level in patients with advanced non-small cell lung cancer (NSCLC).Methods A total of 218 patients with advanced NSCLC treated in our hospital from August 2017 to September 2020 were included in this study, and were randomly divided into control group (109 cases) and study group (109 cases). The control group received taxol and carboplatin (TC) for chemotherapy, and the study group was additionally treated with Fuzheng Sanjie Formula on the basis of the chemotherapy. The short-term efficacy, serological indexes, tumor markers, immune function and adverse reactions were compared between the two groups.Results The disease control rate (DCR) in the study group was higher than that in the control group (P < 0.05). There was no difference in levels of tumor-specific growth factor (TSGF), vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), cytokeratin antigen 21-1 (CYFRA21-1), microRNA-335-5p, CD3⁺ cells, CD4⁺ cells, CD8⁺ cells or CD4⁺ / CD8⁺ ratio before treatments between the two groups (P > 0.05). After treatments, the levels of TSGF, VEGF, TGF-β, CEA, CA125, CYFRA21-1 and CD8⁺ cells in the study group were lower than those in the control group (P < 0.05), while the levels of microRNA-335-5p, CD3⁺ cells, CD4⁺ cells, and CD4⁺ / CD8⁺ ratio in the study group were higher than those in the control group (P < 0.05). In addition, the bone marrow suppression, renal function injury and liver function injury in the study group were milder than those in the control group (P > 0.05).Conclusions Fuzheng Sanjie Formula, as the adjuvant therapy of advanced NSCLC, can improve the short-term curative effect, reduce the chemotherapy toxicity, ameliorate the tumor microenvironment, increase the expression of microRNA-335-5p, and enhance the immune function, thereby improving the prognosis.